Web services relies on software standards. Here is a brief description of what each of the four major Web services standards does.

SOAP (simple object access protocol) Describes how one application dials up a Web service and asks it to perform a task and return an answer. SOAP makes it possible to use Web services for transactions?for example, checking inventory in real-time and placing an order.

UDDI (universal description, discovery and integration) A virtual yellow pages for Web services that lets software discover what Web services are available and how to hook up to them. Companies can maintain an internal UDDI registry to keep track of the Web services they have already built. Major software vendors are working together to develop a public UDDI registry that will enable companies to find each other’s Web services over the Internet.

WSDL (Web services description language) If UDDI is a virtual yellow pages, WSDL is the little blurb associated with each entry that describes what kind of work the Web service can do?for example, it can give you access to a database of ZIP codes.

XML (extensible markup language) A meta-language that lets programmers write their own tags to identify information on a webpage and put it into context (for data related to shoe size and color, for example).